Mathematics – Logic
Scientific paper
Dec 1992
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1992lmip.conf...52m&link_type=abstract
In Lunar and Planetary Inst., International Conference on Large Meteorite Impacts and Planetary Evolution p 52-53 (SEE N93-10112
Mathematics
Logic
Finite Element Method, Hypervelocity Impact, Mathematical Models, Meteorite Collisions, Meteorite Craters, Planetary Craters, Rheology, Structural Basins, Venus Surface, Analogs, Heat Transfer, Nonnewtonian Fluids, Viscoelasticity, Viscous Flow
Scientific paper
More than 50 unequivocal peak-ring craters and multiringed impact basins have been identified on Venus from Earth-based Arecibo, Venera 15/16, and Magellan radar images. These ringed craters are relatively pristine, and so serve as an important new dataset that will further understanding of the structural and rheological properties of the venusian surface and of impact mechanics in general. They are also the most direct analogues for craters formed on the Earth in Phanerozoic time. Finite-element simulations of basin collapse and ring formation were undertaken in collaboration with V. J. Hillgren (University of Arizona). These calculations used an axisymmetric version of the viscoelastic finite element code TECTON, modeled structures on the scale of Klenova or Meitner, and demonstrated two major points. First, viscous flow and ring formation are possible on the timescale of crater collapse for the sizes of multiringed basins seen on Venus and heat flows appropriate to the plant. Second, an elastic lithosphere overlying a Newtonian viscous asthenosphere results mainly in uplift beneath the crater. Inward asthenospheric flow mainly occurs at deeper levels. Lithospheric response is dominantly vertical and flexural. Tensional stress maxima occur and ring formation by normal faulting is predicted in some cases, but these predicted rings occur too far out to explain observed ring spacings on Venus (or on the Moon). Overall, these estimates and models suggest that multiringed basin formation is indeed possible at the scales observed on Venus. Furthermore, due to the strong inverse dependence of solid-state viscosity on stress, the absence of Cordilleran-style ring faulting in craters smaller than Meitner or Klenova makes sense. The apparent increase in viscosity of shock-fluidized rock with crater diameter, greater interior temperatures accessed by larger, deeper craters, and decreased non-Newtonian viscosity associated with larger craters may conspire to make the transition with diameter from peak-ring crater to Orientale-type multiringed basin rather abrupt.
Alexopoulos Jim S.
McKinnon William B.
No associations
LandOfFree
What can we learn about impact mechanics from large craters on Venus? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with What can we learn about impact mechanics from large craters on Venus?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and What can we learn about impact mechanics from large craters on Venus? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1138434